1. Field of the Invention
The present invention relates to servicing gas meters, and more particularly to a bypass valve for providing uninterrupted gas service to a consumer while the gas meter is being serviced.
2. Description of the Prior Art
Gas meters are typically installed on the supply line leading to a residential or commercial consumer and are mounted above ground outside the consumer's building. The meters are thus exposed to the elements and over time suffer some degradation. For this reason, as well as to comply with various governmental codes and regulations, meters must be replaced periodically, usually every ten to fifteen years. Replacing a gas meter has always been a problematic task, especially for residential consumers, because numerous appliances such as water heaters and cooking stoves are equipped with pilot lights that are constantly supplied with gas and thus do not come equipped with shut off valves or automatic pilot light ignition devices. For this reason, when a gas meter is changed the gas service is temporarily shut off and all pilot lights inside the consumer's building are extinguished. Following replacement or service of the meter, the pilot lights must be individually reignited once the gas supply is reestablished and before sufficient gas is released to pose any danger. Thus, the consumer must be present or the gas company employee must be able to gain access into the building to reignite the pilot lights any time a meter is serviced or replaced.
One solution to this problem is to continue to supply gas service to the consumer while the meter is being serviced. Various methods have been proposed in a number of different patents to achieve this goal. A particularly cumbersome method is disclosed in U.S. Pat. No. 3,148,690 to Petersen, wherein a T-fitting is connected between the gas meter and the consumer. During the change out a plastic bag is placed over the T-fitting, a plug sealing the uncoupled end of the fitting is removed, and a probe connected to a gas supply tank is manipulated through the bag to be coupled with the T-fitting and thus supply gas to the consumer while the line from the meter is sealed off. The method of U.S. Pat. No. 3,173,295 to Magleby employs two T-fittings attached to the inlet and the outlet ports of the gas meter, respectively, so as to allow a bypass tube to be connected to the uncoupled end of each T-fitting and thus allow supply line gas to flow around the meter while it is being serviced. This method requires additional equipment installed such as a second T-fitting and mechanisms for shutting off the flow to the meter and thus is not very cost effective.
In U.S. Pat. No. 3,245,257 to Anderson, a T-fitting with an internal two-way valve that can be manually displaced by a plunger to seal off either of two inlets is installed on the distribution side of the gas meter. To service the meter, an uncoupled end of the fitting is unsealed and a plunger assembly including an inlet port connected to an auxiliary gas supply is coupled to the inlet port. The plunger is displaced by pressure from the auxiliary gas supply to move the valve and seal off the inlet from the gas meter. Removing the plug that seals off the uncoupled end of the fitting results in a momentary escape of gas flowing from the meter, with a resultant drop in the gas pressure affecting the consumer gas equipment which may cause the pilot lights to be extinguished and thus defeat the very purpose of the device. A relatively similar arrangement is also disclosed in U.S. Pat. No. 6,654,505 to Jiles.
Another method, disclosed in U.S. Pat. No. 5,287,886 to Russell, employs an override valve installed in series with the gas meter distribution line and including a first ball disposed over the valve inlet and a second ball loosely held in a cage interposed in the flow path of the gas supply. A port in the side of the valve is pneumatically connected to the cage to supply auxiliary gas. During normal operation, the gas pressure in the valve drives the first ball out of the valve inlet to allow gas to flow by, and forces the second ball in the cage to move outward to seal off the side port. During a meter change out, an auxiliary supply is connected to the port to provide gas at a pressure exceeding the service line pressure, thus driving the second ball away from the side port and the first ball against the inlet to seal off the gas flow from the meter. This device appears to be adapted for installation in a vertical orientation only, as the first ball appears to require the aid of gravity to correctly position itself over the valve inlet. In addition, the second ball may be manually displaced during normal operation by inserting a screwdriver or similar device, thus allowing the release of the gas from the line and an interruption of service to the user.
Finally, in U.S. Pat. No. 5,437,300, Winnie et al. propose a bypass valve with a cage similar to the Russell valve, and connected pneumatically to a side port through an elbow fitting. The cage is formed with ports in its side wall and a cylindrical poppet with two flat ends is loosely disposed within the cage to be driven against the elbow fitting inlet by the supply line pressure. When a change out is performed, auxiliary gas at higher pressure than the supply gas is introduced through the elbow fitting to drive the poppet against the other end of the cage and thus seal off the primary gas flow and continue to supply the auxiliary gas to the consumer. Unfortunately, the poppet of this design is prone to freezing, sticking, and jamming in the cage due to factors such as moisture in the line freezing in cold weather, fine dust and other particulates in the line, and the uncontrolled freedom of movement of the poppet within the cage which results in a fluttering motion of the poppet under normal gas flow conditions.
Therefore, the need continues to exist for an apparatus that will ensure a continuous, uninterrupted supply of gas to a consumer while the gas meter is being serviced or replaced and that will successfully withstand the rigors of exposure to the elements, will continue to function without deterioration over extended periods of time, and is configured in a simple, compact, cost effective assembly.